Add __rsub__ and values()

multiset.py

@@ -214,6 +214,11 @@ def __sub__(self, other):
  return NotImplemented
  return self.difference(other)
 
+ def __rsub__(self, other):
+ if not isinstance(other, (Set, BaseMultiset)):
+ return NotImplemented
+ return self._as_multiset(other).difference(self)
+
  def union(self, *others):
  r"""Return a new multiset with all elements from the multiset and the others with maximal multiplicities.
 
@@ -614,6 +619,8 @@ def distinct_elements(self):
  def multiplicities(self):
  return self._elements.values()
 
+ values = multiplicities
+
  @classmethod
  def _as_multiset(cls, other):
  if isinstance(other, BaseMultiset):

tests/test_multiset.py

@@ -589,6 +589,18 @@ def test_sub(MultisetCls):
  assert result is not ms
 
 
+def test_rsub(MultisetCls):
+ ms = MultisetCls('abc')
+
+ with pytest.raises(TypeError):
+ _ = 'abc' - ms
+
+ result = set('abd') - ms
+ assert sorted(result) == list('d')
+ assert isinstance(result, MultisetCls)
+ assert result is not ms
+
+
 @pytest.mark.parametrize(
  ' initial, other, expected',
  [
@@ -985,4 +997,14 @@ def test_str():
 def test_repr():
  ms = Multiset('aabc')
 
- assert repr(ms) == "Multiset({'a': 2, 'b': 1, 'c': 1})"
+ assert repr(ms) == "Multiset({'a': 2, 'b': 1, 'c': 1})"
+
+
+def test_multiplicities(MultisetCls):
+ ms = MultisetCls('aaabbc')
+ assert sorted(ms.multiplicities()) == [1, 2, 3]
+
+
+def test_distinct_elements(MultisetCls):
+ ms = MultisetCls('aaabbc')
+ assert sorted(ms.distinct_elements()) == list('abc')